Early-modern Ryūkyū (1609-1879) was not only under the substantial control of Satsuma (i.e. Japan) but also subordinated to China. While Ryūkyū had accepted the so-called "Sakoku" policy of the Tokugawa Shogunate in which Christianity was strictly prohibited and foreign trade was strongly controlled, it also maintained an annual tributary relation with the Qing dynasty. Ryūkyū and Satsuma concealed their relationship from China, in order not to damage the traditional tributary relationship with China. Through these careful maneuvers, Ryūkyū maintained peaceful relations with the two major powers, as well as contributed to the stability of the East Asia region at this time. This stability, however, was disrupted by the increasingnumber of Western ships arrivingin Ryūkyū in the nineteenth century. The great powers such as Britain, France, and the United States were all attracted by the geopolitical location of Ryūkyū, and many ships called at the port for surveys and negotiation. Furthermore, French and British missionaries began residing in Ryūkyū from the 1840s in defiance of Ryūkyū's policy. Ryūkyū was forced to sign treaties with the U.S. and France in 1854, and 1855 respectively. In order to deal with these unprecedented situations, Ryūkyū trained a group of interpreters (tsūji 通事), Western interpreters who specialized in English and French. Traditionally, Ryūkyū maintained a group of Chinese interpreters, who were residents in Kumemura 久米村, in charge of tributary affairs, as well as dealingwith any unexpected foreigners showingup on Ryukyuan shores, mostly as castaways. The new interpreters, however, were recruited from youngofficials outside Kumemura, signifyingthat encounters with Western powers were considered as somethingRy ūkyū had to commit special resources to deal with. These new interpreters were at the forefront of contact with the Western powers. Their role was a difficult one that required them to defend the interest of Ryūkyū while not provokingthe Western powers to take any serious measures against Ryūkyū. This paper provides a comprehensive examination of these Western interpreters, regarding whom no study exists. The first section of the paper starts with an explanation of the general principles in early-modern Ryūkyū regarding the treatment of castaways. To prevent the exposure of the Ryukyuan-Japanese relationship, castaways were isolated from the local population and closely monitored. If Christian, they were sent to Nagasaki for further interrogation by the Japanese. If not, they were sent to China, and from China to their homelands. The section then continues to analyze the arrival of a British fleet in 1816 that requested an official audience with the kingand to conduct surveys. This was an unprecedented situation for Ryūkyū as no Western nation had visited Ryūkyū for political purpose before. As a means to deal with the unwelcome and hazardous visitors, the Ryūkyū government appointed two young officials to acquire English skills and to perform as interpreters. After difficult negotiations, Ryūkyū successfully persuaded the British to give up their demand for the audience. Thus, this section shows that the interpreters were established at the very moment when traditional ways of dealingwith foreigners had ceased to be functional. The second section analyzes in detail how in the 1840s, with the arrival of missionaries in Ryūkyū, the Ryukyuan government started the full-scale trainingand implementation of the new interpreters. This section describes how the interpreters, while keepingwatch over the missionaries at all times, made much an effort to acquire English and French skills from them. Furthermore, the new interpreters gradually took over the role of the Kumemura interpreters and were charged exclusively with dealing with Western nations. The third section discusses the specific roles of these new interpreters in the treaty negotiations with the U.S. and France. Their job included daily negotiati